Nat Translation

[taos1234]

I am trying to configure a 2600 to router for Internet Access. Not sure why my Nat translations are not working. I'm trying to get inside machines to gain internet access through Ethernet0/0. From the router I can ping to any outside address and I can also ping to any inside address. From any inside machine, I cannot ping past the router. Below is my current configuration:

interface FastEthernet0/0
description Line to DSL
ip address x.x.x.28 255.255.255.240
ip nat outside
speed auto
half-duplex
!
interface Serial0/0
description T1 line to Colo-location
ip address 100.100.100.1 255.255.255.0
ip nat inside
!
interface FastEthernet0/1
description inside LAN
ip address 100.100.200.1 255.255.255.0
ip nat inside
speed auto
half-duplex
!
ip nat pool ovrld x.x.x.1 x.x.x.1 prefix-length 24
ip nat inside source list 3 pool ovrld overload
ip classless
ip route 0.0.0.0 0.0.0.0 x.x.x.1
ip http server
!

access-list 7 permit 100.100.200.0 0.0.0.128


Not a Cisco Expert, can anyone help me out??

 

[svermill]

Where is source list 3? Also, make sure those machines have the appropriate gateway/default address?

 

[taos1234]

This is what I meant:

ip nat inside source list 7 pool ovrld overload

The inside machines have a default gateway of 100.100.200.1

 

[gbiello]

Here's some things I noticed.

The subnet-mask on f0/0 is .240 which tells me you have 16 usable public IP addresses. But the IP address you're using for nat(x.x.x.1) is not in the same range of 16 addresses as the IP you've got on you're f0/0 WAN interface (x.x.x.28). It should be, so you'll need to resolve what public IP range you have, an use an unused IP in there.

Next, try this for a nat access-list:
access-list 7 permit 100.100.0.0 0.0.255.255

Also, in your "ip nat pool' statement, I make the prefix-length equal to my public IP range. Try:
ip nat pool ovrld x.x.x.1 x.x.x.1 netmask 255.255.255.240

Hope this helps,
-gbiello

 

[svermill]

I have to admit that I'm a little rusty on my NAT, but you seem to be translating to a subnet that doesn't match that of your E0/0 interface. Also, you assigned the whole subnet of 100.100.200.1 255.255.255.0 to E0/1 yet your source list only covers half that. Just curious?

 

[taos1234]

Thanks for the help. I addedd a defaut gateway of 66.35.222.1 and everything works fine. Now I need to allow specific ports through the router using access-list. Any suggestions??